Method for the production of a bristle structure on a carrier

Abstract

A method for the production of bristles structures on an arbitrary kind of carrier using a mold tool is described having channels extending from channel walls for shaping bristles, wherein a mold mass for forming the bristles is introduced under pressure into the channels, preferentially using the injection molding technique. Towards this end, the carrier is disposed directly or indirectly onto the mold walls of the channels in such a fashion that the free cross-section of the channels is completely covered and the mold mass is subsequently introduced onto the carrier with a sufficient mold pressure (injection pressure) that the carrier is broken-through in the vicinity of the free cross-section of the channels thereby displacing the carrier material, with the carrier mass subsequently filling the channels.

Description

[0001]This application is the national stage of PCT / EP03 / 04938 filed on May 12, 2003 and also claims Paris Convention priority of DE 102 21 869.2 filed May 15, 2002.BACKGROUND OF THE INVENTION[0002]The invention concerns a method for manufacturing a bristle structure on an arbitrary kind of carrier using a molding tool having channels, extending from a mold wall, for the molding of bristles, wherein a mold mass for forming the bristles is introduced into the channels under pressure.[0003]Bristle products which include, in particular, brushes of every kind, paint brushes as well as brooms are predominantly produced using mechanical methods with which the bristle carrier is initially made having holes and the bristle bundles are mechanically inserted at a subsequent time. With the advent of plastics the brush bodies are manufactured through injection molding or molding processes and the bristles are attached either in the conventional mechanical fashion or, recently, using thermal tec...

AI Technical Summary

Benefits of technology

[0043]The method in accordance with the invention also permits section wise introduction of plastics having different mechanical properties into the molding tool to form the bristles so that the overall bristle structure is built up from bristles having differing properties. Moreover, bristle plastics having different colors can be introduced into the molding tool in sections to provide different types of bristle fields with different visual appearances.

[0044]The method in accordance with the invention always leads to individually standing bristles wi

Problems solved by technology

Bristles of this type can, for practical reasons, only be utilized in limited applications e.g. for hair care or as throwaway brushes.

The reason for the deficient applicability and lack of acceptance is the fact that bristles which are injection molded have a fatigue strength under reverse bending stresses which is inadequate because, in contrast to bristles which are extracted from a spinning process, they do not have the molecular structure which is necessary for stability and which is primarily distinguished by a longitudinal orientation of the molecular chains, parallel to the bristle.

Moreover, these techniques require use of one and the same plastic for the working elements and for the carrier, which, for high quality plastics from which bristles having high quality requirements must be made, leads to corresponding increase in costs.

Nevertheless, the substantial disadvantages in applications remain in consequence of which these types of brushes are only suitable for limited applications.

Moreover, there is no possibility for adaptation of the material used for the carrier and the brushes in response to individual requirements or for differences among the bristles, in particular with regard to mechanical stability, material specific coefficients of friction, color etc.

Second of all, for injection molding technical reasons, the molding channels cannot be sufficiently narrow and deep in order to guarantee proper filling of the mold and as well as to facilitate removal from the mold.

Despite the fact that nylon would be theoretically appropriate to produce bristle-like properties, this does not occur, since a longitudinally oriented molecular structure cannot be effected, at least at the foot of the cleaning element due to

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